Method and system for controlling power provided to an accessory

ABSTRACT

A method for a portable media player to control power provided an accessory is disclosed. The method includes requesting information about the power capabilities of the accessory by the portable media player. The method further includes providing information about the power capabilities of the accessory by the accessory to the portable media player, and utilizing the information to set the power of the accessory. A method and system in accordance with the present invention provides a system that allows a portable media player to obtain information from an accessory concerning its power requirements. A portable media player can then utilize the power requirements information to allow for the powering of the accessory when connected to the portable media player.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser. No. 10/833,689, entitled “Connector Interface System for a Multi-Communication Device”, filed on Apr. 27, 2004, assigned to the assignee of the present application, which is incorporated by reference herein.

This application is related to U.S. patent application Ser. No. 11/519,386, entitled “Method and System for Controlling an Accessory Having a Tuner”, filed on even date herewith, assigned to the assignee of the present application which is incorporated by reference herein.

This application is related to U.S. patent application Ser. No. 11/519,541, “Method and System for Controlling Video Selection and Playback in a Portable Media Player”, filed on even date herewith, assigned to the assignee of the present application which is incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to electrical devices and more particularly to electrical devices such as portable media players that communicate with accessory devices.

BACKGROUND OF THE INVENTION

A portable media player stores media assets, such as audio tracks, video tracks or photos that can be played or displayed on the portable media player. One example of a portable media player is the iPod® media player, which is available from Apple Inc. of Cupertino, Calif. Often, a portable media player acquires its media assets from a host computer that serves to enable a user to manage media assets. As an example, the host computer can execute a media management application to manage media assets. One example of a media management application is iTunes®, version 6.0, produced by Apple Inc.

A portable media player typically includes one or more connectors or ports that can be used to interface to the portable media player. For example, the connector or port can enable the portable media player to couple to a host computer, be inserted into a docking system, or receive an accessory device. There are today many different types of accessory devices that can interconnect to the portable media player. For example, a remote control can be connected to the connector or port to allow the user to remotely control the portable media player. As another example, an automobile can include a connector and the portable media player can be inserted onto the connector such that an automobile media system can interact with the portable media player, thereby allowing the media content on the portable media player to be played within the automobile. In another example, a digital camera can be connected to the portable media player to download images and the like. In many cases the accessory utilizes power when connected to the portable media player.

Accordingly, it may be desirable for the portable media player to control the power provided to and utilized by the accessory when coupled thereto. Therefore, it may also be desirable to provide a method and system for allowing a portable media player to efficiently and effectively control the power of the accessory. The present invention addresses such a need.

SUMMARY OF THE INVENTION

A method for a portable media player to control power provided an accessory is disclosed. The method includes requesting information about the power capabilities of the accessory by the portable media player. The method further includes providing information about the power capabilities of the accessory by the accessory to the portable media player, and utilizing the information to set the power of the accessory.

A method and system in accordance with the present invention provides a system that allows a portable media player to obtain information from an accessory concerning its power requirements. A portable media player can then utilize the power requirements information to allow for the powering of the accessory when connected to the portable media player.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified block diagram of an exemplary portable media player, in accordance with an embodiment of the invention.

FIGS. 2A and 2B illustrate a docking connector in accordance with the present invention.

FIG. 3A is a front and top view of a remote connector in accordance with the present invention.

FIG. 3B illustrates a plug to be utilized in the remote connector.

FIG. 3C illustrates the plug inserted into the remote connector.

FIG. 4A illustrates the connector pin designations for the docking connector.

FIG. 4B illustrates the connection pin designations for the remote connector.

FIG. 5A illustrates a typical FireWire connector interface for the docking connector.

FIG. 5B illustrates a reference schematic diagram for an accessory power source.

FIG. 5C illustrates a reference schematic diagram for a system for detecting and identifying accessories for the docking connector.

FIG. 5D is a reference schematic of an electret microphone that may be within the remote connector.

FIG. 6 illustrates an embodiment of a portable media player coupled to a dongle to provide power to an accessory.

FIG. 7 is a flow chart that illustrates a method for controlling the bus power of a portable media player.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to consumer electronic devices and more particularly to consumer electronic devices such as portable media players that communicate with accessory devices. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.

A method and system in accordance with the present invention provides a system that allows a portable media player to obtain information from an accessory concerning the accessory's power requirements. A portable media player can then utilize this information to provide power to the accessory when the accessory is connected to the portable media player. In one embodiment, commands are utilized to facilitate communication of this power information between the portable media player and the accessory.

In a system and method in accordance with the present invention, the portable media player is a master device and an accessory device is a slave device. In an embodiment, commands are defined to acknowledge a command with status, to set the bus power state, and to obtain a current power state and then set the power state for the accessory. To describe the features of the present invention in more detail refer now to the following discussion in conjunction with the accompanying Figures.

FIG. 1 shows a simplified block diagram for an exemplary portable media player 10 in accordance with an embodiment of the invention. The portable media player 10 includes a processor 124 that pertains to a microprocessor or controller for controlling the overall operation of the portable media player 10. The portable media player 10 stores media data pertaining to media assets in a file system 126 and a cache 106. The file system 126 typically provides high capacity storage capability for the portable media player 10. However, to improve access time to the file system 126, the portable media player 10 can also include a cache 106. The cache 106 may be, for example, random-access memory (RAM). The access time to the cache 106 is substantially shorter than for the file system 126. However, the cache 106 typically does not have the large storage capacity of the file system 126. Further, the file system 126, when active, consumes more power than does the cache 106. The power consumption is particularly important when the portable media player 10 is powered by a battery (not shown). The portable media player 10 also includes additional RAM 122 and a read-only memory (ROM) 120. The ROM 120 can store programs to be executed by the processor 124. The RAM 122 provides volatile data storage, such as for the cache 106.

The portable media player 10 also includes a user input device 108 that allows a user of the portable media player 10 to interact with the portable media player 10. For example, the user input device 108 can take a variety of forms, such as a button, keypad, touch screen, dial, etc. Still further, the portable media player 10 includes a display 110 (screen display) that can be controlled by the processor 124 to display information as well as photos and video tracks to the user. A data bus 113 can facilitate data transfer between at least the file system 126, the cache 106, the processor 124, and other functional blocks. The portable media player 10 also includes a bus interface 116 that couples to a data link 118. The data link 118 allows the portable media player 10 to couple to a host computer that can be a stand alone host computer or part of an interconnected network of computers, such as the Internet or other such distributed systems.

In one embodiment, the portable media player 10 serves to store a plurality of media assets (e.g., songs, videos, photos) in the file system 126. When a user desires to have the portable media player 10 play a particular media item, a list of available media assets is displayed on the display 110. Then, using the user input device 108, a user can select one of the available media assets. The processor 124, upon receiving a selection of a particular media item, such as an audio file, supplies the media data for the particular media item to a coder/decoder (CODEC) 112 via bus 113. The CODEC 112 then produces analog output signals for a speaker 114. The speaker 114 can be a speaker internal to the portable media player 10 or external to the portable media player 10. For example, headphones or earphones that connect to the portable media player 10 would be considered an external speaker. In other applications, media asset files stored on the host computer or in other computers coupled to the host computer by way of the network can be transferred (otherwise referred to as downloaded) to the file system 126 (or the cache 106). These media assets could also be, for example, videos or photos which could be provided to the display 110 via a video processor (not shown) either coupled to or within the processor 124. In this way, the user has available any number and type of media asset files for play by the portable media player 10.

For example, in a particular embodiment, the available media assets are arranged in a hierarchical manner based upon a selected number and type of groupings appropriate to the available media assets. In the case where the portable media player 10 is an MP3 type media player, the available media assets take the form of MP3 files (each of which corresponds to a digitally encoded song or other rendition) stored at least in part in the file system 126. The available media assets (in this case, songs) can be grouped in any manner deemed appropriate. In one arrangement, the songs can be arranged hierarchically as a list of music genres at a first level, a list of artists associated with each genre at a second level, a list of albums for each artist listed in the second level at a third level, a list of songs for each album listed in the third level at a fourth level and so on.

A method and system in accordance with the present invention can be utilized with a portable media player and its associated accessory in a variety of environments. One such environment is within a connector interface system that is described in detail hereinbelow. The connector interface system allows for the media player and the accessory to communicate utilizing interface signals over at least one of the pins of the connector interface system.

Connector Interface System Overview

To describe the features of the connector interface system in accordance with the present invention in more detail, refer now to the following description in conjunction with the accompanying drawings.

Docking Connector

FIGS. 2A and 2B illustrate a docking connector 100 in accordance with the present invention. Referring first to FIG. 2A, the keying features 102 are of a custom length 104. In addition, a specific key arrangement where one set of keys are separated by one length at the bottom and another set of keys are separated by another length at the top of the connector is used. The use of this key arrangement prevents noncompliant connectors from being plugged in and potentially causing damage to the device. The connector for power utilizes a Firewire specification for power. The connector includes a first make/last break contact to implement this scheme. FIG. 2B illustrates the first make/last break contact 202 and also illustrates a ground pin 204 and a power pin 206 related to providing an appropriate first make/last break contact. In this example, the ground pin 204 is longer than the power pin 206. Therefore, the ground pin 204 would contact its mating pin in the docking accessory before the power pin 206, and the risk of internal electrical damage to the electronics of the device is minimized. Further details of an exemplary embodiment for the docking connector 100 are described in U.S. Pat. No. 6,776,660 entitled CONNECTOR, which issued on Aug. 17, 2004 and is incorporated herein by reference in its entirety.

In addition, a connector interface system in accordance with the present invention uses both USB and Firewire interfaces as part of the same docking connector alignment, thereby making the design more compatible with different types of interfaces, as will be discussed in detail hereinafter. In so doing, more remote accessories can interface with the portable media player.

Remote Connector

The connector interface system also includes a remote connector which provides for the ability to output audio and input audio, provides I/O serial protocol, and provides the ability to input video and output video. FIG. 3A is a front and top view of a remote connector 200 in accordance with the present invention. As is seen, the remote connector 200 includes a top headphone receptacle 222, as well as a second receptacle 224 for remote devices. FIG. 3B illustrates a plug 300 to be utilized in the remote connector. The plug 300 allows these features to be provided via the remote connector. FIG. 3C illustrates the plug 300 inserted into the remote connector 200. Heretofore, all these features have not been implemented in a remote connector. Therefore, a standard headphone cable can be plugged in, and special remote control cables, microphone cables, and video cables could also be utilized with the remote connector.

To describe the features of the connector interface system in more detail, provided below is a functional description of the docking connector, remote connector and a command set in accordance with the present invention.

Docking and Remote Connector Specifications

For an example of the connector pin designations for both the docking connector and for the remote connector for a portable media player such as an iPod device by Apple Inc., refer now to FIGS. 4A and 4B. FIG. 4A illustrates the connector pin designations for the docking connector. FIG. 4B illustrates the connection pin designations for the remote connector.

Docking Connector Specifications

FIG. 5A illustrates a typical Firewire connector interface for the docking connector.

Firewire Power:

a) 8V-30V DC IN

b) 10 W Max

Firewire Signal:

a) Designed to IEEE I394 A Spec (400 Mb/s)

USB Interface

In one embodiment, the portable media player provides two configurations, or modes, of USB device operation: mass storage and portable media player USB Interface (MPUI). The MPUI allows the portable media player to be controlled using an accessory protocol. What is meant by an accessory protocol is the software component of the media player that communicates with accessories over a given transport layer.

Accessory Power

FIG. 5B illustrates the accessory power source. The portable media player accessory power pin supplies voltages, for example, 3.0 V to 3.3V+/−5% (2.85 V to 3.465 V) over the docking connector and remote connector (if present). A maximum current is shared between the docking connector and the remote connector.

By default, the portable media player supplies a particular current such as 5 mA. An appropriate software accessory detection system can be employed to turn on high power (for example, up to 100 mA) during active device usage. When devices are inactive, they typically consume less than a predetermined amount of power such as 5 mA current.

Accessory power is switched off for a period of, for example, approximately 2 seconds during the powering up of the portable media player. This is done to ensure that accessories are in a known state and can be properly detected. In one embodiment, accessories are responsible for re-identifying themselves after the portable media player transitions accessory power from the off to the on state.

Accessory power is grounded through the Digital Ground (DGND) pins.

FIG. 5C illustrates a reference schematic diagram for a system for detecting and identifying accessories for the docking connector. The system comprises a resistor (R) to ground that allows the device to determine what type of accessory has been plugged into the docking connector and two identify and detect pins (Accessory Identify (pin 10, FIG. 4A) and Accessory Detect (pin 20, FIG. 4A)).

FIG. 5D is a reference schematic of an electret microphone that is within the remote connector.

For Serial Protocol Communication, two pins used to communicate to and from device (Rx (pin 19, FIG. 4A) & Tx (pin 18, FIG. 4A)). Input and output levels can be, e.g., 0V=Low, 3.3V=High.

As mentioned above, a system and method in accordance with the present invention can be utilized with a command set for allowing a portable media player to provide power to an accessory. It should be understood by one of ordinary skill in the art that although the above-identified connector interface system could be utilized with the commands, a variety of other connectors or systems could be utilized and they would be within the spirit and scope of the present invention. To describe the system and method in accordance with the present invention in more detail refer now to the accompanying description in conjunction with the accompanying figures.

FIG. 6 illustrates an embodiment of a portable media player 502 coupled to a dongle 504 to provide power to an accessory 506 (e.g., a camera). In this embodiment, the system 500 comprises portable media player 502 coupled to a dongle 504 via a connector 507. The connector 507, for example, could be the docking connector whose pinout shown in FIG. 4A. The connector 507 includes the serial pins 508 (Rx and Tx) which couple the portable media player to the dongle 504 and allow for communications thereto. The connector 507 also includes USB pins 510 (D+ and D−).

Accordingly, commands can be utilized across the serial bus 508 of FIG. 4A, for example, to provide power from the portable media player 502 to the accessory 506 over the 5 volt power supply line 512. Alternatively, the dongle 504 could include a power plug 520 to provide the power through the 5 volt power line 512. Therefore, the dongle 504 could either draw power from the portable media player 502 or draw power from a source using the plug 520. A connector 514 couples the dongle 504 to the accessory 506. Typically, the connector 514 comprises a USB connector. However, one of ordinary skill in the art readily recognizes that a variety of connectors could be utilized and their use would be within the spirit and scope of the present invention. Similarly, although a camera is shown as the accessory in FIG. 6, one of ordinary skill in the art ready recognizes a variety of accessories could be utilized and that would be within the spirit and scope of the present invention.

FIG. 7 is a flow chart of a method for controlling power to the accessory in accordance with the present invention. First, information is requested about the power capabilities of the accessory by the portable media player, for example, utilizing serial bus 508 of FIG. 6, via step 602. In the embodiment, a command is sent by the portable media player to obtain the current power state from the accessory.

Next, information is provided about the power capabilities of the accessory by the accessory to the portable media player, via step 604. In the embodiment, a command is sent by the device in response to the current power state command received from the portable media player, via step 606. The command returns the current state of the power supply.

Then, the information is utilized to set the power of the accessory, via step 608. In the embodiment, a command is sent by the portable media player to set the power setting. The accessory will set the power state and respond with a command indicating command completion status.

A method for a portable media player to control power provided to an accessory is disclosed. The method includes requesting information about the power capabilities of the accessory by the portable media player. The method further includes providing information about the power capabilities of the accessory by the accessory to the media player, and utilizing the information to set the power of the accessory. A method and system in accordance with the present invention provides a system that allows a portable media player to obtain information from an accessory concerning its power requirements. A portable media player can then utilize the power requirement information to allow for the powering of the accessory when connected to the portable media player.

Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. For example, the present invention can be implemented using hardware, software, a computer readable medium containing program instructions, or a combination thereof. Software written according to the present invention can be stored in some form of computer-readable medium, such as a memory or CD-ROM, or transmitted over a network, and is to be executed by a processor. Consequently, a computer-readable medium is intended to include a computer readable signal, which may be, for example, transmitted over a network. Also, the principles of the present invention apply to different types of portable media players having different levels of functionality and different form factors. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. 

1-5. (canceled)
 6. A connector interface system for an accessory the connector interface system comprising: an interface adapted to be coupled with a portable media player and to exchange a plurality of commands with the portable media player, the plurality of commands comprising: a first command received by the accessory, the first command for requesting a current power state of the accessory; a second command sent by the accessory, the second command for communicating information about the current power state of the accessory; a third command received by the accessory, the third command for instructing the accessory to set a new power state of the accessory, the new power state being based at least in part on the current power state; and a fourth command sent by the accessory, the fourth command for communicating acceptance of the new power state setting by the accessory.
 7. The connector interface system of claim 6 wherein the power is provided by the portable media player to the accessory.
 8. The connector interface system of claim 6 wherein the power is supplied from an external source to the accessory.
 9. The connector interface system of claim 6 wherein the plurality of commands are communicated over a serial communication channel.
 10. (canceled)
 11. The connector interface system of claim 6 wherein the interface includes a connector having a plurality of signal contacts.
 12. The connector interface system of claim 11 wherein the connector comprises: a keying arrangement, wherein one set of keys are separated by one length and another set of keys are separated by another length, wherein the plurality of signal contacts includes a ground contact and a power contact, wherein the ground contact makes contact with a mating connection before the power contact; wherein the plurality of serial contacts further include at least one USB signal contact, at least one USB power contact, an accessory identify signal contact, at least one video contact, at least one accessory power contact, at least one accessory protocol contact, an accessory detect signal contact, a remote sense signal contact, and at least one line signal-contact, wherein at least one of the contacts is active when a device is coupled to the connector.
 13. A computer readable medium encoded with program instructions which when executed by a portable media player allow the portable media player to control power settings of an accessory, the program instructions including program instructions for: requesting information about a current power state of the accessory by the portable media player; receiving information from the accessory about the current power state of the accessory; and utilizing the information to set a new power state of the accessory by the portable media player.
 14. The computer readable medium of claim 13 wherein the power is provided by the portable media player to the accessory.
 15. The computer readable medium of claim 13 wherein the power is supplied from an external source to the accessory.
 16. The computer readable medium of claim 13 wherein the power is controlled by utilizing commands over serial pins of the portable media player.
 17. The computer readable medium of claim 13 wherein the accessory comprises a digital camera.
 18. An accessory comprising: a device; and an interface in communication with the device and adapted to communicate with a portable media player by exchanging a plurality of commands with the portable media player, the plurality of commands comprising: a first command for requesting a current power state of the accessory, the first command being receivable by the accessory; a second command for communicating information about the current power state of the accessory the second command being sendable by the accessory; a third command for instructing the accessory to set a new power state of the accessory, the third command being receivable by the accessory; and a fourth command for communicating acceptance of the new power setting by the accessory, the second command being sendable by the accessory.
 19. The accessory of claim 18 wherein the power is provided by the portable media player to the accessory.
 20. The accessory of claim 18 wherein the power is supplied from an external source to the accessory.
 21. (canceled)
 22. The accessory of claim 18 wherein the accessory comprises a digital camera.
 23. The accessory of claim 18 wherein the interface includes a connector having a plurality of signal contacts, wherein at least some of the signal contacts are utilized to communicate the plurality of commands.
 24. (canceled)
 25. The accessory of claim 23 wherein the connector comprises: a keying arrangement, wherein one set of keys are separated by one length and another set of keys are separated by another length wherein the plurality of signal contacts includes a ground contact and a power contact, wherein the ground contact makes contact with a mating connection before the power contact; wherein the plurality of signal contacts further includes at least one USB signal contact, at least one USB power contact, an accessory identify signal contact, at least one video contact, at least one accessory power contact, at least one accessory protocol contact, an accessory detect signal contact, a remote sense signal contact, and at least one line signal contact, wherein at least one of the contacts is active when a portable media player is coupled to the connector.
 26. A dongle comprising: a first connector adapted to be coupled to a portable media player; a second connector in communication with the first connector and adapted to be coupled to an accessory, wherein the dongle is configured to exchange a plurality of commands with the portable media player; the plurality of commands comprising: a first command for requesting a current power state of the accessory, the first command being receivable by the dongle from the portable media player; a second command for communicating information about the current power state of the accessory, the second command being sendable by the dongle to the portable media player; a third command for instructing the dongle to set a new power state of the accessory, the third command being receivable by the dongle from the portable media player; and a fourth command for communicating acceptance of the new power setting the fourth command being sendable by the dongle to the portable media player, wherein the dongle is further configured to provide power to the accessory in accordance with the new power state specified by the third command.
 27. The dongle of claim 26 wherein the power is provided from the portable media player to the accessory by the dongle.
 28. The dongle of claim 26 wherein the power is provided from an external source to the accessory by the dongle.
 29. The dongle of claim 26 wherein the plurality of commands are communicated using a serial communication channel.
 30. The dongle of claim 26 wherein the accessory comprises a digital camera.
 31. The dongle of claim 26 wherein the first connector includes a plurality of signal contacts, wherein at least some of the signal contacts are utilized to communicate the plurality of commands.
 32. (canceled)
 33. The dongle of claim 31 wherein the first connector comprises: a keying arrangement, wherein one set of keys are separated by one length and another set of keys are separated by another length wherein the plurality of signal contacts includes a ground contact and a power contact, wherein the ground contact makes contact with a mating connection before the power contact; wherein the plurality of signal contacts further includes at least one USB signal contact, at least one USB power contact, an accessory identify signal contact, at least one video contact, at least one accessory power contact, at least one accessory protocol contact, an accessory detect signal contact, a remote sense signal contact, and at least one line signal contact, wherein at least one of the contacts is active when a portable media player is coupled to the connector.
 34. A method for using an accessory coupled to a portable media player, the method comprising, by the accessory: receiving, from the media player, a request for information indicating power capabilities of the accessory; returning the requested information to the media player; receiving a power setting command from the media player, the power setting command instructing the accessory to set a power state of the accessory to a new power state determined by the media player; and setting the power state of the accessory to the new power state.
 35. The method of claim 34 further comprising, by the accessory: receiving from the media player a power state command, the power state command instructing the accessory to provide the current power state; and in response to the power state command, returning information indicating the current power state to the media player.
 36. The method of claim 35 wherein the information indicating the power capabilities of the accessory includes information identifying a plurality of power states supported by the accessory.
 37. The method of claim 36 wherein the plurality of power states supported by the accessory includes: a high power state associated with active usage of the accessory; and a low power state associated with inactivity of the accessory.
 38. The method of claim 34 wherein the accessory receives power from a power supply located within the media player.
 39. The method of claim 34 wherein the accessory receives power from a power supply external to the media player.
 40. The method of claim 34 wherein the accessory comprises a digital camera.
 41. An accessory for use with a portable media player, the accessory comprising: an interface adapted to be coupled with a portable media player and configured to support an accessory protocol for exchanging with the portable media player commands and information related to power management; and a control module coupled to the interface, the control module being configured to: receive, from the media player, a request for information indicating power capabilities of the accessory; return the requested information to the media player; receive a power setting command from the media player, the power setting command instructing the accessory to set a power state of the accessory to a new power state determined by the media player; and set the power state of the accessory to the new power state.
 42. The accessory of claim 41 wherein the control module is further configured to receive from the media player a power state command, the power state command instructing the accessory to provide the current power state, and in response to the power state command, to return information indicating the current power state to the media player.
 43. The accessory of claim 42 wherein the accessory is configured to support a plurality of power states, the plurality of power states including: a high power state associated with active usage of the accessory; and a low power state associated with inactivity of the accessory.
 44. The accessory of claim 41 wherein the interface includes a power pin adapted to receive power from the media player.
 45. The accessory of claim 41 wherein the interface includes a plurality of pins compatible with a USB interface.
 46. The accessory of claim 45 wherein the plurality of pins compatible with the USB interface includes at least two signal pins.
 47. The accessory of claim 41 further comprising: a dongle having a first end adapted to connect to the interface and a second end adapted to connect to a media player, the dongle comprising a plurality of signal paths adapted to pass electrical signals between the interface and the accessory.
 48. The accessory of claim 47 wherein the dongle further comprises a power supply adapted to deliver power to the accessory. 